Act 1 Scene 5,According to Lady Macbeth's prayer to the evil spirits,what character traits must she possess if she helps Macbeth gain the crown?
Has she considered the negative consequences of her actions?
First she calls upon them to unsex her. As a women, she feels vulnerable and although she may want to kill the king and thus make her husband the new king, she doesn't feel that she is strong enough.
She asks them to empty her of all tender emotions and fill her up instead with direst cruelty. She asks them to shield her against feeling remorse.
She asks them the keep her focused on her "fell purpose" and let nothing get in the way. Her fell purpose, of course, is the death of Duncan.
Instead of the nurturing milk of a mother, she asks that they fill her breast with poison.
In other words, she asks them to give her the strength she feels that she needs to push her husband into killing the king and helping, if necessary. She knows that as a women, her feminine sensibilities would interfere. She feels that only the forces of evil can help her.
Reality is something else entirely as she later learns.